If I'm not mistaken, it's a styrene kit, so if I could offer any advice, it's that cleaning up seams will be as important as it is when you build an airplane with the goal of applying a natural metal finish.
Also, with 1/20 scale, you're getting to a size where you could use your airbrush to apply area base coats, such as on the horse, and on the large areas of exposed skin, if you wanted to.
If you're going to use acrylics, particularly water-based acrylics, I highly recommend using a wet palette. A wet palette consists of a container holding a sponge, and a piece of porous paper for the actual palette. Wet the sponge, lay the paper over it, and put down drops of paint. It makes blending colors easy, and it also lets you use a batch of colors from one session to the next. There are commerically available products, like Masterson, but you can make your own from a take-out container, a kitchen sponge, and kitchen parchment paper or packaging paper.
Above all, have fun, and please share your progress pics!